Section 154.546 - Excess flow valve: Closing flow(a) The rated closing flow of vapor or liquid cargo for an excess flow valve must be specially approved by the Commandant (CG-ENG).(b) An excess flow valve allowed under § 154.532(b) must close automatically at the rated closing flow.CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983